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Multiple Sites Down In SF Power Outage
corewtfux writes with word of a major outage apparently centered on 365 Main, a datacenter on the edge of San Francisco's Financial District. Valleywag initially claimed that a drunken person had gotten in and damaged 40 racks, but an update from Technorati's Dave Sifry says the problem is a widespread power outage. Sites affected include Technorati, Netflix (these display nice "We're Dead" pages), Typepad, LiveJournal, Sun.com, and Craigslist (these just time out).
It's been a long time since I went on a tour of several data centers to locate a new facility for our dot-com. I believe that 365 Main was a facility that does not use a battery UPS. Instead, they have engine-backed flywheel UPS system (see http://www.enterprisenetworksandservers.com/monthl y/art.php?2813 for a description). At the time, they have 10 2-megawatt generators on the roof in a N+2 configuration. The engines are kept heated and are spec'd to go from stop to engage-clutch/deliver-power in 3 seconds. The flywheel can deliver 11 seconds of power so they can fail through a couple of bad engines before running out of flywheel power. They periodidally do a 20-hour load test into a pair of 500,000 watt heat-sinks. Time will tell if this outage was a failure of design, failure of maintenance, or outright malfeasance. But it wasn't supposed to happen. They've got some 'splainin' to do.
As to diesel storage, use of diesel is widespread for emergency use everywhere from hospitals to emergency-services to hospitals. Those systems are run regularly - typically weekly. The use of biocides, stabilizers, and mobile fuel-scrubbing services, and extra filtration systems can maintain the fuel quality. Our colo currently maintains a 1-week fuel-supply and has multiple quick-refuel contracts in place. I can't imagine any colo having less than 24-48 hours in-the-tank with quick-refill on-call.
But one thing that is missing is cooling. Our colo has a typical contract that says something like blah-blah won't exceed 80F for more than 4 hours blah blah. OK, but a rack full of blade servers can crank out 15-20kW of heat load and a data center can heat up real quick without AC. By contract, 150F for 3.5 hours would be in-spec.
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"You are not remembered for doing what is expected of you." - Atul Chitnis
They do, but one of the dirty little secrets of most data centers is that they don't have enough generator capacity for all the cooling. They'll woo you with the generator, the 2,000 gallons of diesel, and N+1 array of UPSes, but when utility power dies, it gets hot very quickly. And some racks must go down.